Controlling apparatus



Dec. 15, 1953 L. E. HARPER 2,662,665

CONTROLLING APPARATUS Original Filed July 5, 1946 2 Sheets-Sheet l IZIcu S O Q E '\J 0 I N \r INVEN TOR. I L YN nus s. HARPER BY Q 04/P%ATTORNEY Dec. 15, 1953 E HARPER CONTROLLING APPARATUS Original FiledJuly 3, 1946 2 Sheets-Sheet 2 INSULATION H 68 EL msuun-wn INSULATOII 47f us 60 H6 69 5 G5 5.9 f" A @l a a; 68 47 (G INSULATION 53\ F1 5 sifi 74I7*---I l FQ Li 57 73 A 69 s l W 6 s8 15 (27 62 7 I7 47 2 GI 53 0INSULATION 64 P 59 211 9.3.

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LYNDUS E. HARPER fi/MZ ATTORNEY Patented Dec. 15, 1953 CONTROLLINGAPPARATUS Lyndus E. Harper, Skokie, Ill., assignor to Omega MachineCompany, Providence, R. I., a corporation of Missouri Originalapplication July 3, 1946, Serial No. 681,385, now Patent No. 2,637,434,dated May 5, 1953. Divided and this application October 23, 1951, SerialNo. 252,747

11 Claims. 1

My invention relates to controlling apparatus, and more particularly tosuch an apparatus for maintaining a predetermined rate of continuousoutput of the controlled device. This application is a division of myapplication Serial No. 681,385, filed July 3, 1946, now Patent No.2,637,434, dated May 5, 1953, on Belt Type Gravimetric Feeder.

My invention particularly relates to controlling apparatus forcontrolling a rate of output adjusting member that is movable in onedirection to increase the rate of output and in the other direction todecrease the rate of output, said controlling means controlling themovement of said adjusting member and the direction of said movement,and comprising a circuit for controlling movement of the adjustingmember in one direction and a circuit for controlling the movement ofthe adjusting member in the opposite direction, and means for selectingand closing the proper circuit to change the adjustment of the device inthe proper direction to maintain said predetermined rate of output.

It is a further purpose of my invention to provide a device of the abovementioned character that is provided with an exact proportioningcontrol. In the invention as illustrated in the drawings, a weightresponsive means is provided for adjusting the feeding means, saidWeight responsive means controlling the position of a member thatcontrols the operation of the circuit selectingmeans above referred to.In the particular apparatus illustrated in the drawings, the controllingmeans controls feeding means and said controlling means will adjust therate of feed as soon as the scalebeam or similar Weight responsivemember or other member responsive to the rate of output of the devicemoves out of balanced or normal position and will continue to adjust thefeeding or similar means to remedy the rate of output to restore themember to balanced or normal position by changing the adjustment of theoutput adjusting member, such as the feeding means, all of the time thatthe member responsive to the rate of output is out of its normal orbalanced position, and by maintaining the output adjusting member in itsadjusted position all of the time that the output responsive or weightresponsive member is in its normal, predetermined or balanced position.

It is a further purpose of my invention to provide controlling meansthat comprises means that not only adjusts the rate of output the wholetime that the rate of output responsive member, such as a scalebeam, isnot in normal or balanced position, but which adjusts the outputadjusting member in accordance with the direction of movement of theoutput responsive member out of normal position and in accordance withthe amount of such movement, thus adjusting the rate of output, such asthe rate of feed of a feeding member, in proportion to the amount thatthe scalebeam or similar output responsive member is out of balance orout of normal position due to the fact that the rate of feed or outputis not the desired rate of feed or output.

More particularly my invention comprises controlling means, includingelectrically actuated means for adjusting the rate of output controllingmember so as to maintain a constant rate of output, and means forcontrolling the operation of the electrically actuated means whichcloses the circuit to operate the electrically actuated means foradjusting the output controlling member for a length of timeproportional to the amount of movement of the output responsive memberout of normal position and thus proportional to the amount that the rateof output is out of adjustment.

In the specific form of the invention illustrated,

7 the controlling means is shown as being used for controlling feedingmeans and the controlling means comprise scales that have means thereonfor supporting a predetermined length of a conveyor to which material isfed, and a scalebeam that has an adjustable weight thereon forcontrolling the rate of feed of the feeding means, to feed the amount ofmaterial to counterbalance said Weight onto a length of said conveyorequal to that being weighed at any one time by the scales, the means forcontrolling the feeding means comprising a circuit controlling meansaiTected by the position of the scalebeam in such a manner thatcontrolling circuits are closed for periods dependent upon the amountthat the scalebeam is out of balance, to change the adjustment of thefeeding means in direct proportion to the amount that the scalebeam isout of balance due to the rate of feed of the material being differentfrom that to which the weight responsive means is adjusted.

Preferably, my improved controlling means comprises a cam member rotatedat a constant rate of speed, which is so shaped that a flexibly mountedmember will be in contact with the cam member for a length of timedependent upon the amount that the scalebeam or similar outputresponsive member is out of balanced position, or out of normalposition, to control an adjusting circuit to close it for acorresponding length of time.

It is a particular purpose of my invention to provide controlling meansof the above mentioned character, that includes a motor which isreversible and which operates at a constant rate, so that the length oftime of operation thereof will determine the amount of movement of apart driven by the motor in a given direction, and thus the amount thatthe apparatus being controlled. is adjusted in that particulardirection, the operation of said reversing motor being controlled bymeans of an output responsive device, such as a scalebeam, through meanssuch as above described, so as to operate in a direction dependent uponthe direction in which the scalebeam or other output responsive memberis out of normal position, and for a length of time determined by theamount that such an output responsive member is out of such normalposition.

It is a very important purpose of my invention to provide controllingapparatus of the above mentioned character that is so arranged that whenthe output responsive member, such as the scalebeam, is in its normal orbalanced position, the controlling circuits will remain open so that theadjusting member will remain in its previously adjusted position as longas said output responsive member remains in its normal position.

It is another important purpose of my invention to provide controllingmeans of the above mentioned character, that is so constructed andarranged that the contact pressure of electrical contact means that maybe used as a part thereof, will have no effect on the balance ormovement of the scalebeam or other output responsive member in thedirection in which it moves when responding to the weight that is on thepredetermined length of conveyor that is operating over the weighingmeans or other output measuring means.

Other objects and advantages of my invention will appear as thedescription of the drawings proceeds. I desire to have it understood,however, that I do not intend to limit myself to the particular detailsshown or described, except as defined in the claims.

In the drawings:

Fig. 1 is a diagrammatical View partly in elevation and partly insection, showing my improved controlling apparatus as applied to oneform of feeding means.

Fig. 2 is a fragmentary elevational view on an enlarged scale, partlybroken away, of the contact operating end of the scalebeam, andcooperating means for controlling the rate of output of the devicecontrolled by my improved controlling apparatus.

Fig. 3 is a fragmentary top plan view of the cooperating contacts andassociated parts, and

Fig. 4 is an elevational View, taken partly in section, substantially onthe line 4- 3 of 3, with the parts in the position shown in Fig. 2.

Referring in detail to the drawings, my improved controlling apparatusis shown as being applied to a feeding device that comprises a scale inhaving a platform H upon which is mounted in any suitable manner, as bymeans of a frame having a portion l2 mounted on the platform, and sidemembers 13 mounted on said member 12, the rollers Hi over which theconveyor belt l5 operates. Said side members It may be provided with aguide plate l6 underlying the conveyor belt l5 between the rollers It tosupport the belt and prevent sagging thereof, should this be founddesirable. The weight of material that is on the conveyor belt itbetween the rollers Hi will operate the scale mechanism to determine theposition of the scalebeam H, the scale mechanism being of any suitablecharacter, such as ordinarily provided for platform scales, and notbeing shown in the drawings, as the particular structure thereof is nota part of this invention. A sliding weight l8, or similar member, isprovided on the scalebeam for adjusting the apparatus to obtain abalance of the scalebeam when the desired rate of feed of material istaking place that the amount of material fed, that is on the conveyorbelt between the rollers M, will exactly counterbalance the weight [8.Obviously a scale can be provided on the scalebeam that will indicatethe rate of feed in any desired units for the setting of the weight italong the length of said scalebeam.

In the form of the invention shown in Fig. 1 the material that is fed tothe conveyor belt [5 is fed from a hopper l9, which has an opening 20 inan inclined bottom wall 2! thereof, the size of which is adjustable bymeans of a slide 22, so as to obtain the desired rate of feed throughsaid opening of the material 23 that is in the hopper to a conveyor belt2 3. The position of the slide or door 22 is, preferably, determined bymanually adjustable means, comprising any suitable selflocking adjustingmeans, such as the rack 25 and pinion 25, the rack 25 being fixed on theslide 22 and the pinion 26 engaging said rack and being rotated by meansof a crank 2?, the shaft carrying said crank 21 and pinion 25 beingmounted in any suitable manner on the body of the hopper l9, as by meansof bracket members 28.

The conveyor belt 24 operates over a pair of rollers 29, which aremounted in any suitable manner on a frame having the longitudinallyextending members 30, the shaft at of the roller 29 having a pulley 32fixed thereon, over which a belt 33 operates, which is driven by meansof a pulley 34 of a variable speed transmission 35, the output speed ofwhich is the speed of the pulley 34 and is exactly proportional to theposition of a follower, or followers, along the axis of a cam, or cams,which are rotated at a constant speed, said variable speed transmissionbeing of substantially the same character as that shown in my Patent No.2,404,231, on Variable Speed Transmission, patented July 16, 1946. Theaxial adjustment of the followers of the variable speed transmission 35is determined by means of the shaft 36, rotation of said shaft in onedirection adjusting the followers in a direction parallel to the axis ofthe cam shaft in such a direction as to increase the rate of rotation ofthe output pulley 34, and rotation of the shaft 36 in the reversedirection adjusting said followers in a direction parallel to the axisof the cam shaft so as to decrease the rate of rotation of the outputpulley 34. The means for driving the variable speed transmissioncomprises a constant speed motor 37, which drives a belt 38 thatoperates over a pulley 39 on the input shaft of the variable speedtransmission 35.

Mounted adjacent the scalebeam i7 is a constant speed electric motortil, the same being, preferably, a small synchronous alternating currentmotor, such as ordinarily utilized for operating small mechanisms, suchas electric clock mechanisms. Conductors H and 42 extend from the linewires 43 and 44 to said motor to to constantly rotate the same at aconstant speed. The motor 40 is shown as being mounted on the horizontalframe member 50 of the scale It (see Figs. 2 and 4), being mounted bymeans of angle brackets .45 on a bracket 5! dependin from t frame member50. The motor has a shaft 46 on which is fixed. .a cam 41 to rotatetherewith, said shaft operating in a bearing 48 in the bracket 51, andhaving any suitable means for holding said cam in fixed position axiallyof said shaft, said shaft being, preferably, provided with a reducedportion to provide a shoulder at 45, suit able means 52 being providedto hold said cam against the shoulder 49 so that the same will be inposition to properly cooperate with the con-- tact members to bedescribed below.

The insulating bracket 53 is fixed on th end of the scalebeam in anysuitable manner, as by means of the screws 54. Secured to said bracket5.3 of insulation by means of the screws 5'5 and 5,6 is a contact member66 of resilient material, and secured to said bracket 53 by means ofscrews 51 and 5.8 is a contact member 61 of resilient material. Thecontact member 66 has an end portion 59 extending at an oblique angle tothe body portion of said contact member tapering to a blunt contactpoint, and the contact member 5! has an obliquely extending portion 60bent back on itself and tapering to a blunt contact point.

An adjusting screw 6! is provided for the contact member 68 and asimilar adjusting screw 62 is provided for the contact member 5?, by

means of which said contact members can be nates in an offset orshoulder 14, joining the low point of said cam with the hi h pointthereof. In the position of the parts shown in Figs. 2, 3 and 4 thecontact members 66 and 6! are just cleared by the high point 15 of thecam. There is no necessity for any great amount of mecranical clearance,due to the fact that a very low voltage current will pass throu h thecircuit in which the contacts 66 or 61 are located. Should the scalebeambecome slightly out of balance due to an excessive amount of material 23being fed by the conveyor member 2 to the conveyor memher [5, theshoulder '14 on the cam member 4'! will engage the contact member 55,moving it from the position shown in Fig. 4 into a position so as toslide along on the face 63 of the cam 5?. The contact 6i; will be. ineifect, brushed aside, to the extent that it will lightly engage saidface 63 of the cam 41, the blunt point on said contact member 66 ridingalong on the face 63 until it intersects the rising face 13 of the cam,whereupon it is immediately sprung back to its normal position. The camis provided with a beveled or rounded edge, 64 leading from theperipheral edge of said cam to the face 6.3, to guide the contactmembers into, engagement with said face.

It will be obvious that the rising face ill of the cam can be so shapedthat'the end of the contact 66, or the corresponding end of the contact67, will enga e the face 63 of the cam :37 for a period of time thatwill be in proportion to the amount that the scalebeam is out or"balance, and that if the scalebeam is out of balance as much or morethan the height of the offset or shoulder M, the contact of the cam facewith the particular contact member 66 or 51, as the case may be, will'becontinuous u til the feed issadiusted in a manner to be describedbelow,to restorcthescalebeam to a balanced condition. Preferably, therate of rotation of the cam 41 and the speed of the conveyor I5 is suchthat a length of conveyor I5 equal to that located between the pulleysl4 will pass over the scale for each rotation of the cam shaft 46. Whilethis arran ement is preferred, any fixed ratio of therate of rotation ofthe cam shaft and the rate of travel of the conveyor belt Hi can beutilized that may be preferable.

It will be obvious that if the cam 4! rotates once for each length ofconveyor belt equal to that between the pulleys [4 that is weighed, ifthe adjustment of the feed is accomplished by a single rotation of thecam 47 actuating the controlling device to accomplish such adjustment,the scalebeam I! will again be balanced, and on the next rotation of thecam the high point 15 of the cam will clear the contact 66 and nofurther adjustment of the feeding means will occur. If the adjustmenthas not been completely successful in getting the proper rate of feedfor which the device is set, then on the next rotation of the cam 41 acontact will again be made in the manner above described, but of a muchshorter duration, to further adjust the feeding means in a properdirection to obtain the desired rate of feed and to balance thescalebeam l1. It will be noted that due to this manner of operation ofthe device by proper design of the cam, there will be no so-calledhunting of the apparatus to obtain a balance of the scalebeam, that is,the scalebeam will not first be thrown out of balance in one directionand then in another direction, due to the fact that the adjusting meanswill adjust the feed too much first in the one olirection, causing anoverbalanccin the one direction, and necessitating another adjustment inthe other direction to correct that overbalance.

Referring to Fig. 1 it will be noted that the scalebeam I 1 is providedwith a ground connection 18. The metallic bracket 5| or any otherconvenient part of the frame conductively connected with, the cam 41through the shaft 46 has a conductor extending therefrom, whichconstitutes a ground connection. The contact 65 is connected through theconductor 68 with the winding of a relay 19, which is connected throughthe conductors 80, BI and 82 with thesecondary winding '83 of atransformer having a primary winding 84, the other end of the secondarywinding being connected with the ground connection 85. The contact 6! isconnected through conductor 69 with the winding of a relay 86, fromwhich the conductor 81- leads to the conductor 8| connected with thesecondary 83 of the transformer in the manner above described. Theprimary 84 of said transformer is connected with the line wires 43' and44 by means of the conductors 88 and 89. The conductors 68 and 69 areconnected with the contact, members 66 and 61, respectively, throughscrews 56 and 58', which also serve as binding screws. Accordingly, whenthe contact 66, engages the cam 41- the relay 19 is operated,

and when the contact 6.1 engages the cam 41 the relay 86 is actuated.

When the winding of the relay I9 is energized to attract the armature9.0, which is normally biased to engage the stop member 9 I, saidarmature 90, which is a switching element, engages the switching element92 to connect the conductor 93 with the conductor 44. The conductor 93leads to one terminal of the reversing motor 94, which drives the shaft36. A conductor 95 extends from the central terminal of the motor 94 tothe conductor 43. The terminals to which the conductors 93 and'95 areconnected are such that when the circuit is completed through theseconductors to the motor 94 it will be rotated in a direction to rotatethe shaft 39 in the proper direction to increase the speed of the shaft34 by means of the variable speed transmission 35. Thus, when thescalebeam II lowers out of balanced position the circuit to the motor 94will be closed to adjust the variable speed transmission, to increasethe speed of the output pulley 34 and thus of the conveyor belt 24 andthis adjustment will continue as long as the contact 66 engages the cam41, which will be as long as the scalebeam I1 is out of balance, so asto be below its normal or balanced position. This adjustment willobviously adjust the amount of material 23 fed to the conveyor belt I5,so as to obtain the rate of feed desired for the setting of theadjustable weight I9 on the scalebeam II.

On the other hand, if the contact 91 engages the cam 41, because thescalebeam I! is raised above its balanced position, then the relay 89will be energized, attracting the armature 93, which is normally biasedto engage the stop means 91, causing the armature, which is a switchingmember, to engage the stationary contact 98, completing the circuitbetween the line conductor 99, and the conductor I99, which leads to thethird pole of the motor 94. The conduotor 99 has such phase relation tothe conductor 44 that when the conductors 43 and 99 are connected withthe terminals of the motor 94 through the conductors 95 and I99 thedirection of rotation of the motor 94 will be reversed, and thedirection of rotation of the shaft 33 will be reversed, thus causing anadjustment of the variable speed transmission 35 such that the rate ofrotation of the pulley 34 will be decreased. and the rate of feed of thematerial 23 by means of the conveyor belt 24 will be decreased, so thatthe scalebeam U will be brought back into a balanced position due to thefact that the proper amount of material is being fed over the length ofthe conveyor I5 located between the pulleys I4 to counterbalance theweight I8 for the adjusted position of said weight, this beingaccomplished in a similar manner to that above described in connectionwith the contact member 66.

The variable speed mechanism is so constructed that the adjustment ofthe rate of rotation of the pulley 34 on the output shaft of thevariable speed transmission will be in direct proportion to the amountthat the shaft 36 rotates in a given direction. Thus the length of timethat the circuit is closed to the motor 94 through either the conductors93 and 95, or the conductors 95 and I 99, will determine the amount ofadjustment of the speed of the output shaft on which the pulley 34 ismounted and thus of the speed of the conveyor 24, which determines therate of feed to the weighing conveyor I5.

Means is provided for halting the operation of the conveyor I5 in casethe hopper I9 becomes empty, and for halting the operation of theconveyor 24 should there for some reason be such a great over-supply ofmaterial 23 being fed thereto that the normal adjusting means does notpromptly adjust the rate of travel of the conveyor 24 to feed the properamount of material 23 to the conveyor I5. The means provided for thispurpose prevents any excessive underload or overload of the conveyor I5.Said means comprises a relay WI and a relay I92, the

relay I M being provided with an armature I93, and the relay I92 with anarmature I94, the armature being so biased in the case of each relaythat it will engage normally with a contact to close the circuit whenthe windings of the relays I9I or I92 are not energized, and engage thestops indicated at I and I93 when said windings are energized. The relayI9I controls the operation of the motor I91, which drives the conveyorI5 through the belt I98, while the relay I92 controls the operation ofthe motor 32, which drives the variable speed mechanism 35 and thus theconveyor 24. V

A conductor I99 extends from the conductor 82 and has branches H9 andIII that are each connected to one end of the windings of the relays I9Iand I92, respectively. A conductor II2 leads from the winding of therelay I9I to a flexible contact member H3 and a conductor II4 leads fromthe other end of the winding of the relay I92 to a flexible contactmember H5. The contact members H3 and H5 are insulatingly mounted on abracket I I6 depending from the member 59 of the scale. The saidcontacts engage any suitable means mounted on the scalebeam II out ofalignment with the weight I8, so as to not interfere with the adjustmentthereof and can readily engage a rigid contact I I7 mounted on arearwardly extending bracket on said scalebeam, upon the scalebeam beingmoved a predetermined amount out of balanced position. Thus, if thescalebeam I'I drops further than would normally occur due to suchvariations in the feed as can be properly adjusted by means of thepreviously described rate of feed adjusting means, or under excessiveunderload on the conveyor I5, or emptying of the hopper I9, the circuitthrough the winding of the relay I9I will be completed through theconductors 92, I99, II9, II2, contact II3, contact III, and through thescalebeam I I to the ground connection I8, whereupon the armature I93will be attracted so as to open the circuit to the motor I9'I, which isnormally closed due to engagement of the contact I93 with a stationarycontact IIB, which is connected by means of the conductor II9 with aconductor I29 extending from the line wire 44, the movable contactmember or armature I93 being connected by means of the conductor I2Iwith one terminal of the motor I91, the other terminal of which isconnected with the line wire 43 by means of a conductor I22. Thus, whenthe parts are in the position shown in Fig. l, the circuit for operatingthe motor I9'I extends from the line wire 44 through the conductors I29,II9, IZI and I22, to the line wire 43, and upon excessive underload onthe conveyor I5 the circuit is opened by means of the relay I III tostop the operation of the motor I97.

The movable switching member or armature I94 cooperates'with a fixedcontact member I23, which is connected through a conductor I24 with theconductor I29, while the armature or movable contact member I 94 isconnected with a conductor I25, which extends to one terminal of themotor 31, the other terminal of the motor being connected by a conductorI26 with the line wire 43. Accordingly, the circuit through the motor 31is completed when the parts are in the position shown in Fig. 1 from theline wire 44 through the conductors I29, I24, I25, and the conductor I26to the line wire 43. However, if there is an excessive amount ofmaterial being supplied to the conveyor 24 so as to cause an overload ofthe material 23 to be fed to the conveyor [5, such that the rate of feedadjusting means can not properly take care thereof quick; ly, thescalebeam I! will rise so that the contact member will be engaged by thecontact Iii, which will close-the circuit through the winding of therelay Hi2 through the conductors82, 109, H1, H4, contact member. H5,contact HT, and the scalebeam IT to the ground connection 18, causingthe armature Hi4 tube attracted, break: ingthe operating circuit of themotor 31 and thus stoppingthe operation of the conveyor 24 until theoverload condition on the conveyor I E has been corrected, due to thefact that no mate rial is being fed to the conveyor l5 rrum the conveyor24. u a

When the s'calebe'am is in balance" therrate of feed will be maintaineddue to the fact that the contact member 41 will be out of engagementwith both contacts 66 and 61. In case the rate of feed is less than itshould be, then the circuit will be completed by engagement of themember 41 With the contact 66 to speed up the belt 24' the proper amountto obtain the desired rate of feed to correct the deficiency in the rateregistered by the descent of the scalebeam sufiiciently to causedisengagement of the members 41 and 65. When the contact 41 engages thecontact 51, the reverse movement of the parts will take place to reducethe rate of feed to bring the scalebeam I"! back into balance.- If thescalebeam is in balance there will be no change in the rate of feed.Thus a controlling means is provided, which will, under all normaloperating conditions, maintain substantially a steady rate of output atthe desired rate for which the apparatus is adjusted, without any socalled hunting action of adjustment back and forth through the balancedor normal condition of the weighingmeans or other output responsivemember.

What I claim is: v I l. Controlling apparatus for maintaining apredetermined rate of continuous output of a device, comprising a rateof output adjusting member movable in one direction to increase saidrate of output and in the opposite direction to' decrease said rate ofoutput, and means controlling the movement of said adjusting member andthe direction of said movement, comprising a circuit for controllingmovement of said adjusting member in one direction, a circu t forcontrolling movement of said adjustingmember in the opposite direction,a member mounted for movement in opposite directions, said member havinga position determined by the rate of output of said device and having apredetermined position as long as said output is at said predeterminedrate and moving to positions onop posite sides of said predeterminedposition when ever the rate of output of said device is; above or belowsaid predetermined rate, and cooperat ing means for selecting one ofsaid circuits re-- sponsive to the position of said output rateresponsive member, said cooperating means including meanscontinuously'rotating in the same direction, and means engaging withsaid continuously rotating means upon movement of said member out ofsaid predetermined position in either direction to select a circuit andclose said selected circuit to change the adjustment of said device, oneof said cooperating means being mounted to move with said member, andmeans for opening both said circuits to maintainthe adjustment of saiddevice upon disengagement of said cooperating means, said output rateresponsive member holding said cooperating means- 10 out or engagementwhen in its predetermined position.v i

2. Controlling apparatus for maintaining a predetermined rate ofcontinuous output of a device, comprising a rate V of output adjustingmember movable in one direction to increase said rate of output and inthe opposite direction to decrease saidrate of outputand meanscontrolling the amount of movement of said adjust ing member and thedirection of said movement, comprising a circuitcontrolling the amountof movement of said adjusting member in one direction, a circuitcontrolling the amount of move ment of said adjusting member in theopposite direction, a member mounted for movement in oppositedirections, said member having a position determined by the rate ofoutput of said device and having a predetermined position as long assaid output is at said predetermined rate and moving to positions onopposite sides of said predetermined position whenever the rate ofoutput of said device is above or below said predetermined rate,cooperating means for selecting one of said circuits responsive to theposition of said output rate responsive member, said cooperating meansincluding means continuously rotating in the same direction, and meansengaging with said continuously rotating means, and means for moving oneof said cooperating means with said output rate responsive member toselect one of said circuits and close said selected circuit to changethe adjustment of said device upon movement of said output rateresponsive member out of said predetermined position, said cooperatingmeans being related to maintain the closed condition of said selectedcircuit for an interval determined by the amount of movement of saidrate responsive member out of said predeter= mined position, and meansfor moving said ad- L justin member in the direction controlled by theselected circuit as long as said circuit remains closed and open bothsaid circuits tomaintain the adjustment of said device upon said outputrate responsive member moving into said predetermined position.

3. Controlling apparatus for maintaining a predetermined rate ofcontinuous output of a device, comprising a rate of output adjustingmember determining the rate of output of said device by its position,said adjusting member being movable in one direction to increase saidrate of output and in the opposite direction to decrease said rate ofoutput, and means controlling the amount of movement of said adjustingmember and the direction of said movement, comprising a circuit forcontrolling movement of said adjusting member in one direction, acircuit for controlling movement of said adjusting member in theopposite direction, a member mounted for movement inopposite directions,said member: having a position determined by the rate of output of saiddevice and having apredetermined position as long as said output is atsaid predeter mined rate and moving to positions on opposite sides ofsaidfpredetermined position whenever the rateof output of said device isabove or below said predetermined rate a distance dependent upon thevariation of the output of said device from said predetermined rate, andcooperating means for selecting one of said circuits responsive to theposition ofsaid output rate responsive member, said cooperating meansincluding means continuously rotating in the same direction and circuitclosing means controlled by said rotating means and the position of saidoutput rate responsiv'e member to select a circuit and close said 11selected circuit to change the adjustment of said device upon movementof said output rate responsive member out of said predeterminedposition, and means for moving said adjusting member in the directioncontrolled by the selected circuit as long as said circuit remainsclosed, said cooperating means opening both said circuits to maintainthe adjustment of said device whenever said output rate responsivemember is in said predetermined position, said rotating member being soshaped that said selected circuit will be closed to continue changingthe adjustment of said device for an interval proportional to the amountof movement of said output rate responsive member out of saidpredetermined position.

a. Controlling apparatus for maintaining a predetermined rate ofcontinuous output of a device,- comprising a rate of output adjustingmember determining the rate of output of said device by its position,said adjusting member being movable in one direction to increase saidrate of output and in the opposite direction to decrease said rate ofoutput, and means controlling the amount of movement of said adjustingmember and the direction of said movement, comprising a circuit forcontrolling movement of said adjusting member in one direction, acircuit for controlling movement of said adjusting member in theopposite direction, a member mounted for movement in oppositedirections, said member having a position determined by the rate ofoutput of said device and having a predetermined position as long assaid output is at said predetermined rate and moving to positions onopposite sides of said predetermined position whenever the rate ofoutput of said device is above or below said predetermined rate adistance dependent upon the variation of the output of said device fromsaid predetermined rate, and cooperating means for selecting one of saidcircuits responsive to the position of said output rate responsivemember, said cooperating means including rigid cam-like means of fixedcontour continuously rotating in the same direction and circuit closingmeans controlled by said rotating means and the direction and distanceof said output rate responsive member from said predetermined positionto select a circuit and close said selected circuit to change theadjustment of said device upon movement of said output rate responsivemember out of said predetermined position, said cam-like member being soshaped as to open both said circuits to maintain the adjustment of saiddevice whenever said output rate responsive member is in saidpredetermined position and close the selected circuit for'an intervalproportional to the distance said rate responsive member is out of saidpredetermined position.

5. Controlling apparatus for maintaining a predetermined rate ofcontinuous output of a device, comprising a rate of output adjustingmember determining the rate of output of said device by its position,said adjusting member being movable in one direction to increase saidrate of output andin the opposite direction to decrease said rate ofoutput, and means controlling the amount of movement of said adjustingmember and the direction of said movement, comprisin a circuit forcontrolling movement of said adjusting member in one direction, acircuit for controlling movement of said adjusting member in theopposite direction, a member mounted for movement in oppositedirections, said member having a position determined by the rate ofoutput of said device and having a predetermined position as long'assaid output is at-said predetermined rate and moving to a position onopposite sides of said predetermined position whenever the rate ofoutput of said device is above or below said predetermined rate adistance dependent upon the variation of the output of said device fromsaid predetermined rate, and cooperating means for selecting one of saidcircuits responsive to the position of said output rate responsivemember, said cooperating means including rigid cam-like means of fixedcontour continuously rotating in the same direction and circuit closingmeans controlled by said rotating means and the direction and distanceof said output rate responsive member from said predetermined positionto select a circuit and close said selected circuit to change theadjustment of said device upon movement of said output rate responsivemember out of said predetermined position, and means for moving saidadjusting member in the direction controlled by the selected circuit aslong as said circuit remains closed, said cam-like member being soshaped as to open both said circuits to maintain the adjustment of saiddevice whenever said output rate responsive member is in saidpredetermined position and that the selected circuit is maintainedclosed to continue changing the adjustment of said device for aninterval proportional to the amount of movement of said output rateresponsive member out of said predetermined position.

6. Controlling apparatus comprising an adjusting member movable in onedirection to increase the output rate of the controlled device and inthe opposite direction to decrease the output rate of the controlleddevice, and means controlling the amount and direction of movement ofsaid adjusting member, compri ing a circuit for controlling movement ofsaid adjusting member in said one direction, a circuit for controllingmovement of said adjusting member in said other direction, a membermounted for movement in opposite directions from a normal position inresponse to the output rate of said device, and means for closing one ofsaid circuits upon movement of said output rate responsive member out ofnormal position including rotatable contact means, means forcontinuously rotating said rotatable contact means at a constant rate,contact means cooperating with said rotatable contact means, and meansfor moving one of said contact means into a position corresponding tothat of said output rate responsive member.

7. Controlling apparatus comprising an adjusting member movable in onedirection to increase the output rate of the controlled device and inthe opposite direction to decrease the output rate of the controlleddevice, and means controlling the amount and direction of movement ofsaid adjusting member, comprising a circuit for controlling movement ofsaid adjusting member in said one direction, a circuit for controllingmovement of said adjusting member in said other direction, a membermounted for movement in opposite directions from a normal position inresponse to the output rate of said device, and means for closing one ofsaid circuits upon movement of said output rate responsive member out ofnormal position including rotatable contact means, means forcontinuouslyrotating said rotatable contact means at a constant rate, contact meanscooperating with said rotatable contact means comprising a contactmember in each of said circuits, and means for moving one of saidcontact means into a position corresponding to that of said output rateresponsive member, said rotatable contact means being shaped to be outof engagement with both said contact members whenever said rateresponsive member is in normal position.

8. Controlling apparatus comprising an adjusting member movable in onedirection to increase the output rate of the controlled device and inthe opposite direction to decrease the output rate of the controlleddevice, and means controlling the amount and direction of movement ofsaid adjusting member, comprising a circuit for controlling movement ofsaid adjusting member in said one direction, a circuit for controllingmovement of said adjusting member in said other direction, a membermounted for movement in opposite directions from a normal position inresponse to the output rate of said device, and means for closing one ofsaid circuits upon movement of said output rate responsive member out ofnormal position including rotatable contact means, means forcontinuously rotating said rotatable contact means at a constant rate inthe same direction, contact means cooperating with said rotatablecontact means comprising a contact member in each of said circuits, andmeans for moving one of said contact means into a position correspondingto that of said output rate responsive member, said rotatable contactmeans being so shaped as to enage one of said contact members for aninterval proportional to the movement of said rate responsive member outof normal position.

9. Controlling apparatus comprising an adjusting member movable in onedirection to increase the output rate of the controlled device and inthe opposite direction to decrease the output rate of the controlleddevice, and means controlling the amount and direction of movement ofsaid adjusting member, comprising a circuit for controlling movement ofsaid adjusting member in said one direction, a circuit for controllingmovement of said adjusting member in said other direction, a membermounted for movement in opposite directions from a normal position inresponse to the output rate of said device, and means for closing one ofsaid circuits upon movement of said output rate responsive member out ofnormal position including a rotatable cam of fixed contour, means forcontinuously rotating said cam at a constant rate, and contact meansmovable with said rate responsive means comprising a contact member ineach of said circuits cooperating with said cam to close its circuitonly during engagement with said cam.

10. Controlling apparatus comprising an adjusting member movable in onedirection to increase the output rate of the controlled device and inthe opposite direction to decrease the output rate of the controlleddevice, and means controlling the amount and direction of movement ofsaid adjusting member, comprising a reversing motor, a circuit foroperating said motor in one direction, a circuit for operating saidmotor in the opposite direction, a member mounted for movement inopposite directions from a normal position in response to the outputrate of said device, and means for closing one of said circuits uponmovement of said output rate responsive member out of normal positionincluding rotatable contact means, means for continuously rotating saidrotatable contact means at a constant rate, contact means cooperatingwith said rotatable contact means, and means for moving one of saidcontact means into a position corresponding to that of said output rateresponsive member.

11. Controlling apparatus comprising an adjusting member movable in onedirection to increase the output rate of the controlled device and inthe opposite direction to decrease the output rate of the controlleddevice, and means controlling the amount and direction of movement ofsaid adjusting member, comprising a reversing motor, a circuit foroperating said motor in one direction, a circuit for operating saidmotor in the opposite direction, a member mounted for movement inopposite directions from a normal position in response to the outputrate of said device, and means for closing one of said circuits uponmovement of said output rate responsive member out of normal positionincluding rotatable contact means, means for continuously rotating saidrotatable contact means at a constant rate, contact means cooperatingwith said rotatable contact means comprising a contact member in each ofsaid circuits, and means for moving one of said contact means into aposition corresponding to that of said output rate responsive member,said rotatable contact means being so shaped as to engage one of saidcontact members for an interval proportional to the movement of saidrate responsive member out of normal position and to be out ofengagement with both said contact members whenever said rate responsivemember is in normal position.

LYNDUS E. HARPER.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 404,867 Ricketson June 11, 1889 674,947 Tolchard May 28, 19011,151,990 Balzer Aug. 31, 1915 1,777,670 Hausman Oct. 7, 1930 1,787,176Spitzglass Dec. 30, 1930 1,916,420 Harrison July 4, 1933 2,116,778Brayer May 10, 1938 2,276,383 Francis Mar. 17, 1942 2,366,075 WeyandtDec. 26, 1944 2,404,231 Harper July 16, 1946 2,637,434 Harper May 5,1953

